diff --git a/src/TextUI/TestRunner.php b/src/TextUI/TestRunner.php
index 00c2fcf860c..bc167dd14e7 100644
--- a/src/TextUI/TestRunner.php
+++ b/src/TextUI/TestRunner.php
@@ -158,7 +158,7 @@ public function doRun(Test $suite, array $arguments = [], bool $exit = true): Te
 
         $this->handleConfiguration($arguments);
 
-        if ($arguments['columns'] < 16) {
+        if (\is_int($arguments['columns']) && $arguments['columns'] < 16) {
             $arguments['columns']   = 16;
             $tooFewColumnsRequested = true;
         }